Not OP: I played it with my girlfriend exclusively so far, so I only have 2P experience. The game perfectly introduces new mechanics over time. You start with the basics - you only score with quests (special tiles that you have to add regular tiles to, to finish them) and your biggest city/forest/field/river/railway, that’s it for the first game. You’ll most likely score less than 100 points in the first few games, but you’ll still get “progression points” that’ll unlock new mechanics after your 2nd or 3rd game.
These mechanics allow you to score progressively more points and make the game more complicated as you go on. We got a new mechanic from the progression track or the challenge cards (which you’ll unlock with the track) pretty much every round. These new mechanics are usually a new special tile with extra scoring opportunities (which also means you’ll be able to place more tiles as you go on).
We finished the progression track and almost all challenges after 14 rounds I think. After that you can play for highscores or reset the game and start over from the beginning. This also leads to one of the best features: the included insert is beautifully organized. You have a slot for the quest tiles, for the regular and special tiles (with room to spare for the new tiles you’ll unlock), the quest markers, all the little tokens you get, the reward boxes and the tracking/scoring sheets. The reward boxes have a card that tells you what belongs into it if you want to reset the game. It is just so well thought through. It takes only 2 mins to set up (you have to shuffle all the tiles, sorting the quest markers and placing all the challenge cards so you remember them is optional but doesn’t take long) and 5 mins max to put away.
I would recommend playing with one group/partner until you are finished with the progression track. Sorting out all the tokens/tiles/challenges you have unlocked with one group but not the other is possible but would add considerably to the setup or put away time.
I can wholeheartedly recommend it, maybe with the caveat that you should make sure that each player draws their own tile and has the option to make placement decisions on their own (they even say so in the rules that the drawing player has the final say). For us it became a really cooperative experience and we actively thought through our options. It is one of the few games I can play several rounds after another because it is fast enough for the “one more round” effect, but strategic enough to keep me thinking.
In Wingspan there are only very limited ways of “destructively” interacting with other players, to me only two come to mind:
You take away birds someone else wants to draw, either by taking them yourself or by refreshing the birdbath with an ability. You can’t steal from someone’s hand or board (not that I think you should be able to). This usually hasn’t that much impact, because there are many birds with similar stats and/or abilities and there are so many birds, you can’t really play for a certain combo anyway.
You limit someone’s ability to take or use the food they want by (a) taking it from the pool of rolled dice, but similarly to 1., there are several ways to roll them again or generate them directly. Or (b) take their acquired food with a bird’s ability, but they always get something in return, either a specific resource or they can draft from the pool, it’s rarely punishing und usually at least neutral.
Apart from that there is nothing that would impact your gameplan that is in the hands of another player. You always get the same amount of turns, always at the same time and the first player marker moves predictably. The last round is also pretty lame if you play with the basegame, because laying eggs if you’ve got the space is the best move to take at the end - the expansions fixed that though by giving you less eggs.
Terraforming Mars on the other hand (I haven’t played the others more than once) let’s you compete for bordspace and the resources on them, which already makes it way more important and competitive to get established on the board early on, at least if someone else is doing it. You also compete for the progression track bonuses that directly give more VPs and influences the game’s length. If everyone pushes temperature/O2/oceans early on and you know the game will end around round 11 instead of round 14, you will have to adapt your strategy quite a bit.
I still think Wingspan is a great game, but it certainly isn’t for everyone. Imo it would have fit in better into the normal “Spiel des Jahres”-Category instead of the “Kennerspiel” one, that probably rubbed some people the wrong way/set wrong expectations.